PTL 1 has proposed a personal authentication system that authenticates a user, based on whether or not input data for user authentication and pre-registered data are consistent with each other and a moving distance determined based on a current position and a current time, and determines whether to display information.
In this personal authentication system, predetermined registration data for the user, and the position and date and time when a mobile terminal device was used in the past are stored in a storage device in association with each other. If user data which is input to the mobile terminal device and current position data of the mobile terminal device are received, it is determined whether or not a first authentication condition is satisfied, in which the user data input to the mobile terminal device is consistent with predetermined registered data. In addition, it is determined whether or not a second authentication condition is satisfied, in which a distance between the position at the time of use in the past being stored in the storage device and the present position of the mobile terminal device is a movable distance within a time difference between the date and time of use in the past being stored in the storage device and the present date and time. Then, if at least the first authentication condition and the second authentication condition are satisfied, the personal authentication is completed.
Accordingly, it is possible to perform personal authentication of the user of the mobile terminal device with a relatively simple structure, using the current position and the current time of the mobile terminal device.
PTL 1 discloses a personal authentication system that determines the user is the owner, based on a distance between the current position information and the past position information of the mobile communication device. However, there is no disclosure about handling the information after the authentication. Thus, for example, there is a problem that when the owner of the mobile communication device is changed, the information from after the change which is accumulated after the change and the information from before the change which is accumulated before the change (unnecessary information for the owner after the change) are mixed and provided to the owner after the change.